[WP 34s] Matrix multiplication procedure
06-22-2015, 10:32 PM (This post was last modified: 06-22-2015 10:36 PM by Marcio.)
Post: #1
 Marcio Senior Member Posts: 438 Joined: Feb 2015
[WP 34s] Matrix multiplication procedure
Hello all,

Would you be kind enough as to explain with an example how to do matrix multiplication in the 34s? So far I have only been able to invert them, mostly because all it takes is store the data in $$R_n$$ and then call $$M^{-1}$$ with the descriptor in $$x$$. Quite easy.

As to multiply matrices, the manual says the descriptors should be in $$z$$ and $$y$$, the problem however is that I don't quite understand what should be in $$x$$.

Very much appreciated.

Marcio
06-22-2015, 11:30 PM (This post was last modified: 06-22-2015 11:38 PM by Thomas Klemm.)
Post: #2
 Thomas Klemm Senior Member Posts: 1,447 Joined: Dec 2013
RE: [WP 34s] Matrix multiplication procedure
WP 34S pocket reference

M×                z y x → r
Take two matrix descriptors y and z, and the
integer part of x as the base address of the re-
sult. Returns (Z)·(Y)=(X). All calculations are
done in internal high precision (39 digits).
The fractional part of x is updated to match
the resulting matrix - no overlap checking is
performed.

(06-22-2015 10:32 PM)Marcio Wrote:  the problem however is that I don't quite understand what should be in $$x$$.

That is the matrix-descriptor of the result. Make sure it doesn't overlap with z and y.

HTH
Thomas
06-22-2015, 11:38 PM (This post was last modified: 06-23-2015 12:09 AM by Marcio.)
Post: #3
 Marcio Senior Member Posts: 438 Joined: Feb 2015
RE: [WP 34s] Matrix multiplication procedure
(06-22-2015 11:30 PM)Thomas Klemm Wrote:
(06-22-2015 10:32 PM)Marcio Wrote:  the problem however is that I don't quite understand what should be in $$x$$.

That is the matrix-descriptor of the result. Make sure it doesn't overlap with z and y.

HTH
Thomas

Quite obvious after this little hint.
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